Online analyzer

ABSTRACT

An on-line analyzer for analyzing a test sample, having a measuring device, which includes at least one measuring cell and at least one optoelectronic component. The measuring device determines, at at least one wavelength, the transmission or absorption of electromagnetic radiation passing through the test sample and provides measurement signals. The analyzer further includes a control/evaluation unit, which evaluates the measurement signals delivered by the measuring device and makes analysis data available. The measuring cell and the control/evaluation unit are located spatially separated from one another; the at least one optoelectronic component of the measuring device is assigned to the control/evaluation unit; the measuring cell and the at least one optoelectronic component are connected together via a light wave conductor.

The invention relates to an on-line analyzer for analyzing a testsample.

On-line analyzers are marketed by the assignee under the trademarkSTAMOLYS. The analyzers are used in, among other things, the monitoringand optimizing of cleaning performance of a clarification plant, themonitoring of aeration tanks and clarification plant effluent, or thecontrol of filler dosing. Examples of parameters measured and monitoredinclude the concentration of ammonium, phosphate or nitrate in a testsample. The analysis of a test sample occurs on the basis of knownmeasuring methods that do not need to be gone into in greater detailhere.

On-line analyzers register daily information preferably continuously asa function of time. They deliver, on the one hand, desired informationreliably with respect to the ongoing operation of the plant; on theother hand, information respecting possibly required changes in theprocess technology are furnished. On the basis of the analysis data, itis possible at times to achieve quite considerable savings in operatingmeans and operating costs.

The working procedure in an on-line analyzer containing a calorimetricmeasuring device is roughly as follows: a pump fills the permeate—thus,the collected test sample - into a mixing container. A reagents pumpfeeds to the test sample a suitable reagent in a specified mixing ratio.The reagent reacts with the test sample, whereby the test sample turnscolor in a characteristic manner. A measurement of the absorption ortransmission of radiation directed through the reacted test sample isdetermined by means of a photometer or a spectrometer. The absorption,or transmission, as the case may be, delivers information on theconcentration of a chemical element or a chemical compound in the testsample. Preferably, the temperature of the photometer in the STAMOLYSanalyzer is controlled thermostatically, in order that the intendedreaction between permeate and reagent can proceed reproducibly and becompleted within a short time.

In the case of known analyzers, the photometer with measuring cell,together with the pumps for supply of permeate, reagent and/or cleaningagent, and the valves for switching between internal cycles(calibration, cleaning) , are all accommodated on one mounting frame.Consequently, the electronics for amplifying the optical signals of theoptoelectronic components, e.g. the photodiodes, are located in theso-called wet part of the on-line analyzer. In order to protect thesensitive optoelectronic components of the photometer, or spectrometer,as the case may be, against wetness and electromagnetic interference, itis absolutely necessary in the known instances to accommodate theelectronics in a separate, sealed, protective housing. In general, theknown solution involves relatively many individual components: On theone hand, its assembly is rather complex; on the other hand, the spacerequirement for the known solution is relatively large.

An object of the invention is to provide an on-line analyzer, in whichthe wet part and the electronics part are completely decoupled from oneanother.

The analyzer of the invention includes a measuring device, whichdetermines the transmission or the absorption of electromagneticradiation of at least one wavelength as it passes through the testsample, and provides the measurement signal, and a control/evaluationunit, which evaluates the measurement signal delivered by the measuringdevice and makes analysis data available. The measuring device includesat least one measuring cell and at least one optoelectronic component.Measuring cell and control/evaluation unit are located spatiallyseparated from one another. The at least one optoelectronic component ofthe measuring device is assigned to the control and evaluation unit.Additionally, at least one light wave conductor, such as a fiber opticconnection, is provided, over which the measuring cell and the at leastone optoelectronic component are connected with one another.

By way of the invention, it is thus possible, for the first time, toseparate spatially, and decouple completely, from the optoelectronic andelectrical components, all components of the analyzer that come intodirect contact with the test sample. Especially, in the case of use of aphotometer, the sensitive electronics for amplifying the opticalmeasurement signals of the photodiodes are situated outside of the wetpart of the analyzer. In this way, a damaging of the sensitiveelectronic parts in the case of a burst hose is reliably avoided.Moreover, the on-line analyzer of the invention has excellentEMC-properties.

Preferably, the measuring device is a single channel or a plural-channelphotometer. However, a spectrometer can also be used for the on-lineanalyzer of the invention.

The optoelectronic components can be light-emitting diodes, a photodiodeor a diode-array spectrometer.

In an advantageous further development of the on-line analyzer of theinvention, at least one plug-connector is provided, via which the atleast one optoelectronic component is connectable with the light waveconductor. In addition to this, an embodiment with plural light waveconductors is provided, wherein the light wave conductors are collectedin a light wave conductor bundle. This embodiment provides an orderlyarrangement of the light wave conductors.

In the case of a two-channel photometer, two light wave conductors areused, with one light wave conductor, or channel, for the measuringwavelength and one light wave conductor, or channel, for the referencewavelength.

In the case of a diode-array spectrometer, a fiber optic light coupleris provided, via which the optoelectronic components of the spectrometerand the light wave conductors are connected together. Using the lightwave conductor technology, it is possible, instead of coloredlight-emitting diodes or photodetectors, to use a broadband light sourcefor illumination of the measuring cell. For the spectrally resolvedmeasurement, a diode-array spectrometer with fiber optic light couplingis, as already indicated, made use of. In these ways, the differentmeasured variables of a test sample can be determined with one piece ofhardware. Additionally, some measured variables in the UV/VIS or NIRspectral regions can be measured directly, thus without reagents.

A preferred further development of the analyzer of the inventionprovides that the optoelectronic components and the electronic and/orelectrical components of the measuring device and/or of the analyzer arelocated on at least one circuit board. Especially, it is provided thatall optoelectronic components are located on the main board, on whichthe components of the amplification electronics are also to be found.This practice leads to reduction of manufacturing costs.

Additionally in connection with the analyzer of the invention, at leastone pump unit is provided, via which the test sample and/or a reagentand/or cleaning agent is introduced into the measuring cell. Accordingto one form of embodiment, the control/evaluation unit assumes completecontrol of the operation of the on-line analyzer. Preferably, thecontrol/evaluation unit, the so-called electronics part, is located inthe upper region and/or in the back region of the on-line analyzer;additionally, at least one dividing wall is provided, which separatesthe electronics part from the wet part, where, among other things, themeasuring cell and/or the pump unit are/is to be found. Since theelectronics part is now well sealed-off from the wet part, thepreviously required, separate, protective housing for the sensitiveelectronic parts of the photometer can be omitted.

The invention will now be explained in greater detail on the basis ofthe drawings, the figures of which show as follows:

FIG. 1: a front view of an on-line analyzer of the invention; and

FIG. 2: a view of the embodiment of the measuring device component ofFIG. 1.

FIG. 1 is a front view of one form of embodiment of the on-line analyzerof the invention. FIG. 2 is a detail view of the embodiment of themeasuring device 2 shown in FIG. 1.

Housing 10 of the on-line analyzer 1 of the invention is separated bydividing wall 20 into an electronics part 7 and a wet part 21. In theillustrated example, dividing wall 20 is arranged horizontally andseparates the electronics part 7, located in the upper region of housing10, from the wet part 21, located in the lower part of the housing 10.In the wet part 21 are found all components of the on-line analyzer 1that come in direct contact with the liquid test sample. In theillustrated case, these are the channel switching valves 14, the pumps11, the shut-off valves 13, the dosing loop 12, the measuring cell 3 andthe receptacles 15.

The measuring device 2 includes a measuring cell 3 and a plurality ofoptoelectronic components 4. While the measuring cell 3 is to be foundin the wet part 21 of the on-line analyzer, the optoelectroniccomponents 4 are located in the electronics part 7. The measuring celland the optoelectronic components 4 are, according to the invention,connected via light wave conductors 5. The light wave conductors 5 andthe optoelectronic components 4, same as for the light wave conductors 5and the measuring cell 3, are connected together using plug connectors6. By this feature, it is possible, for example, to perform a simpleexchanging of a measuring cell 3 in favor of another measuring cell 3 ofdifferent thickness. Of course, the light wave conductors 5 can also beconnected permanently with the optoelectronic components 4 or themeasuring cell 3. The illustrated case also concerns a so-calledtwo-channel photometer: The measuring and reference beams are coupledin, and out, via separate light conductors 5.

Also located in the electronics part 7 is the control/evaluation unit19, which is responsible for the sequence control of the on-lineanalyzer 1 and for the evaluation and for the providing of the analysisdata. Both the sequence control and the winning of the measured valuesare subjects already known in the state of the art, so that a detailingof these subjects will not be made here. Preferably, all electronic andelectrical components 4, 19 are located on a single board 18.

In the lower region of the wet 21 are located the receptacles 15, forstorage of reagents and cleaning agents. The reacted test samples andused cleaning agents are discharged through the outlet tube 17.

1-12. (canceled)
 13. An on-line analyzer for analyzing a test sample,having: a measuring device comprising at least one measuring cell and atleast one optoelectronic component, said measuring device determines, atat least one wavelength, the transmission or the absorption ofelectromagnetic radiation passed through the test sample and providesmeasurement signals; a control/evaluation unit, which evaluates themeasurement signals delivered by said measuring device and makesanalysis data available; and at least one light wave conductor, wherein:said measuring cell and said control/evaluation unit are locatedspatially separated from one another; said at least one optoelectroniccomponent is assigned to said control/evaluation unit; said at least onelight wave conductor is provided, via which said measuring cell and saidat least one optoelectronic component are connected together.
 14. Theon-line analyzer as claimed in claim 13, wherein: said measuring devicecomprises one of a one-channel and a plural-channel photometer.
 15. Theon-line analyzer as claimed in claim 13, wherein: said measuring devicecomprises a spectrometer.
 16. The on-line analyzer as claimed in claim13, wherein: said optoelectronic component comprises one of: alight-emitting diode, a photodiode and a diode-array spectrometer. 17.The on-line analyzer as claimed in claim 13, further having: at leastone plug-connector, via which said optoelectronic component isconnectable with said light wave conductor.
 18. The on-line analyzer asclaimed in claim 13, wherein: a plurality of light wave conductors isprovided, collected together in a light wave conductor bundle.
 19. Theon-line analyzer as claimed in claim 14, wherein: in the case of atwo-channel photometer, two light wave conductors are used, with onechannel provided for the measuring wavelength and one channel for thereference wavelength.
 20. The on-line analyzer as claimed in claim 15,wherein: in the case of a diode-array spectrometer, a fiber optic lightcoupler is provided, via which said optoelectronic components and saidlight wave conductors are connected together.
 21. The on-line analyzeras claimed in claim 13, wherein: said optoelectronic components and theelectronic and/or electrical components of said measuring device and/orof the analyzer are arranged on a circuit board.
 22. The on-lineanalyzer as claimed in claim 13, further having: at least one pump unit,via which the test sample and/or a reagent are/is supplied into saidmeasuring cell.
 23. The on-line analyzer as claimed in claim 13,wherein: said control/evaluation unit directs sequential control of theon-line analyzer.
 24. The on-line analyzer as claimed in claim 21,wherein: said control/evaluation unit is located in the electronicscomponents part in the upper region of the on-line analyzer; and atleast one dividing wall is provided, which separates the electronicscomponents part from a wet part, in which, among other things, saidmeasuring cell and said pump unit are arranged.